Coordination-Driven Tetragonal Prismatic Cage and the Investigation on Host-Guest Complexation

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Coordination-driven hosts are known to encapsulate guests via noncovalent interactions.
• Porphyrin and terpyridine are versatile building blocks in supramolecular chemistry.

Purpose of the Study:

• To design and synthesize a novel prism-shaped host molecule integrating porphyrin and terpyridine moieties.
• To investigate the host's ability to encapsulate various guests through distinct binding interactions.
• To explore the utility of the host in confined chemical reactions.

Main Methods:

• Synthesis of ligands and prismatic complexes.
• Characterization using electrospray ionization mass spectrometry (ESI-MS), TWIM-MS, NMR spectrometry, and single-crystal X-ray diffraction.
• Guest encapsulation studies via ESI-MS, NMR spectrometry, and transient absorption spectroscopy.
• Binding constant and stability determination using UV-Vis spectrometry and gradient tandem MS (gMS2).

Main Results:

• Successful synthesis of a new prism host with a long cavity, combining porphyrin and terpyridine units.
• Demonstrated encapsulation of both bisite and monosite guests through axial coordination and π-π interactions.
• Characterization confirmed the structure and binding properties of the host-guest complexes.
• A selectively confined condensation reaction was successfully performed within the host cavity.

Conclusions:

• A novel porphyrin- and terpyridine-based prism host has been developed.
• The host exhibits efficient guest encapsulation via multiple noncovalent interactions.
• This system offers potential for detecting pyridyl- and amine-containing molecules and for confined catalysis.